Stirrer



March 20, 1951 R, A, MCDONALD 2,545,824

STIRRER Filed Nov. 13, 1948 INVENTQR Richard A. McDonald Patented Mar. 20, i951 STIRRER Richard A. McDonald, Easton, Pa., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application November 13, 1948, Serial No. 59,797

3 Claims. 1 g

This invention relates to a stirrer of the centrifugal pump type adapted to be positioned in and operated in relatively shallow tanks such as used in the treatmentof photographic film and paper.

In photographic work it is ofttimes desirable to have eflicient'agitation of thin layers of liquid without causing excessive turbulence or. froth: ing, particularly so that aerial oxidation will be held to a minimum. The developing, fixing and washing of photographs is usually done in relatively shallow trays or tanks and it is desirable to stir the liquid in contact with the photographs so that a fresh layer of solution or water replaces the used'solutions adjacent to the face of the photograph.

An object of the invention is to provide a stirrer of this nature having a novel discharge orifice.

A further object of this invention is to provide a stirrer with the intake and exhaust ports adapted for stirring a thin layer of liquid.

These and other objects are attained by the means described herein, a preferable form of which is illustrated in the drawings. In general the invention relates to a rotary stirrer comprising an enclosed chamber, rotary means within said chamber for establishing centrifugal flow, an intake opening in said chamber near the central axis thereof and a discharge opening at the periphery of said chamber comprising an 81011? gated thin slit.

In the drawings:

Fig. 1 is a side elevational view partly in section of the stirrer of this invention associated with a suitable operating motor,

Fig. 2 is a bottom view of the stirring device as indicated by the lines 2-2 of Fig. 1 and Fig. 3 is an elevational view of the various parts of the stirrer shown in Fig. 1 unassembled.

Referring to the drawings, there is shown a motor ID on motor stand ll connected to the stirrer blades l2 by means of shaft l3. Supports I4 connect the motor stand with the stirrer chamber l5 by means of a collar l6 adapted to be held immovably on bushing I! by means of a set screw l8. The blades l2 are held in a suspended position in chamber l5 by means of the shaft bushing 20 held to the shaft by set screw 2! and in operation frictionally engaging the top of bushing l1. Flat disc-like pump chamber I5 is formed of two plates 23 and 24. The plate 23 has a hole .in the center sufiicient to admit the shaft l3 and plate 24 is provided with an enlarged central aperture 25 throug wh ch means as by-set screws 30.

the liquid entersthe stirrer and a collar 26 of sufficient thickness to allow the plates l2 to rotate freely between plates 23 and 24. The collar is discontinuous at the top edge thereof forming an elongated semi-circular slit 28 in the chamber when plate 23 is in place on top of plate 24. The plates are held together by known is forced by centrifugal action out through the slit in the chamber so that a very thin fan shaped stream of liquid comes from the stirrer.

It will be obvious that the power may be transmitted to the blades by means other than the electric motor, that the bearing surfaces may contain ball bearings or the like, etc. It will further be obvious that the blades may be of anv one number of types such as cupped or propeller-like but that the flat blade illustrated is particularlyv desirable. Alternatively also the liquid entrance port may be on the upper side of the pump chamber and the chamber may then rest on the bottom of a vessel.

Essentially, the stirrer is a centrifugal pump, but has several features which have not previously been found in such pumps. One of the new features of the stirring mechanism is the slit outlet which causes the liquid being pumped to be ejected in a sheet-like form rather than as a solid stream. Stirrers of this type may be made small enough to circulate a 1 inch thick layer of liquid or even less. The slit may be substantially circular instead of /3 semi-circular, as illustrated, and the stirrer may thus be placed in the middle of a tray and the liquid caused to flow in all directions, although it is an important advantage of the preferred form of the invention that it need not be placed in the middle of a vessel. The enclosed stirring blade renders it less hazardous for fragile equipment and photographic supplies. By placing a mesh over the opening at the bottom of the stirring devices, the stirrer can be operated in the presence of glass beads, clay plate chips, etc.

Besides photographic uses and the like, the stirrer may also be used for the preparation of oil-in-water or water-in-oil emulsions due to the high shearing force developed by the blades and the rapid ejection of the thin sheet of liquid into the main body.

It may, of course, be used in vessels other than shallow pans and thus has general utility in laboratory use. Its enclosed blades are a safety factor.

Other alterations and modifications may be made within the scope of the followin claims.

I claim:

1. A rotary stirrer adapted to emit a thin sheet of liquid within a shallow liquid body, comprising an enclosed disc-like chamber, a plurality of rotary blades within said chamber adapted to establish centrifugal flow, an inlet near the center of said chamber adapted to admit liquid flowing by gravity into said chamber, and a discharge opening at the periphery of said chamber comprising an elongated thin slit adapted to direct a thin sheet of liquid away from the central axis of said chamber.

2. A rotary stirrer adapted to emit a thin sheet of liquid within a shallow liquid body, comprising an enclosed disc-like chamber, a plurality of rotary blades within said chamber adapted to establish centrifugal flow, an inlet near the center of said chamber adapted to admit liquid flowing by gravity into said chamber, and a discharge opening at the periphery of said chamber comprising an elongated thin slit around substan- 4 tially the entire periphery of said chamber and adapted to direct a thin sheet of liquid away from the central aXis of said chamber.

3. A rotary stirrer adapted to emit a thin sheet of liquid within a shallow liquid body, comprising an enclosed disc-like chamber, a plurality of rotary blades within said chamber adapted to establish centrifugal flow, an inlet near the center of said chamber adapted to admit liquid flowing by gravity into said chamber, and a discharge opening at the periphery of said chamber comprising an elongated thin slit in about one-third of the periphery of said chamber and adapted to direct a thin sheet of liquid away from the central axis of said chamber.

RICHARD A. MCDONALD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,057,478 Cowles Oct. 13, 1936 2,342,559 Sebald et al Feb. 22, 1944 FOREIGN PATENTS Number Country Date 145,696 Switzerland Mar. 15, 1931 

